KR20140133392A - Methods for transmitting and receiving data with multiple base stations and apparatuses thereof - Google Patents

Abstract

The present invention relates to a processing method and apparatus for data retransmission in an environment in which a macro cell and a small cell are constructed by overlapping each other through individual base stations, and a method and apparatus for retransmitting data in an environment in which a terminal constituting a dual connection with a first base station and a second base station is not received A method of processing data, the method comprising: receiving an upper layer signaling including retransmission request path information from a first base station; and requesting retransmission of a data unit not received from the first and second base stations in a PDCP entity of the terminal And transmitting the retransmission request status report to the RLC entity of the UE peered to the RLC entity of the first base station in the PDCP entity of the UE.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for transmitting and receiving data through a plurality of base stations,

 The present invention relates to a processing method and apparatus for retransmitting data between a terminal and a base station in an environment in which a macro cell and a small cell are constructed by overlapping through individual base stations.

As communications systems evolved, consumers, such as businesses and individuals, used a wide variety of wireless terminals.

In a mobile communication system such as LTE (Long Term Evolution) and LTE-Advanced of the current 3GPP series, there is a demand for a high-speed, large-capacity communication system capable of transmitting and receiving various data such as video and wireless data beyond a voice-oriented service.

For such a high-speed, large-capacity communication system, a technique for increasing the capacity of a terminal using a small cell is required.

In this case, the terminal can form a double connection with the base station providing the macro cell and the base station providing the small cell to transmit and receive data, and form at least one bearer with each base station.

However, in a case where a mobile station establishes a dual connection with each base station to transmit and receive data, window termination occurs in the course of performing reordering of lost data due to a data transmission delay between the respective base stations, There is a problem that a delay may occur.

According to the above-mentioned demand, the present invention provides a method for reducing the window suspension problem in the reordering process of lossy data in a situation where a terminal and a base station transmit / receive data, or reducing a delay in transmitting data in order And apparatus.

According to an aspect of the present invention, there is provided a method for processing data that a terminal constituting a dual connection with a first base station and a second base station can not receive, comprising the steps of: Generating a retransmission request status report for requesting retransmission of a data unit not received from the first and second base stations in the PDCP entity of the UE, and generating a retransmission request status report for the RLC entity of the first base station in the PDCP entity of the UE And delivering a retransmission request status report to the RLC entity of the peered terminal.

In addition, the present invention provides a method for transmitting data with a base station constituting a dual connection to a terminal together with a second base station, the method comprising: transmitting upper layer signaling including retransmission request path information to a terminal; Receiving a retransmission request status report for receiving a retransmission request of a data unit that is not received from a base station and transmitting a retransmission data unit to a RLC entity of a base station in a PDCP entity of the base station.

According to another aspect of the present invention, there is provided a method for transmitting data between a first base station and a second base station, the method comprising: receiving an upper layer signaling including retransmission path information from a first base station; Receiving a retransmission request status report for requesting retransmission of data units not received from the first base station and the second base station in the RNC entity of the first base station and receiving retransmission request status reports from the RNC entity of the UE peered to the RLC entity of the first base station, And delivering the unit.

In addition, the present invention provides a method for processing data not received by a base station having a dual connection with a second base station, the method comprising: transmitting upper layer signaling including retransmission path information to a terminal; Generating a retransmission request status report for requesting retransmission of data units not received from the UE, transmitting a retransmission request status report to the RLC entity of the base station in the PDCP entity of the base station, and transmitting a retransmission request status report And receiving the requested retransmission data unit through the RLC entity of the base station.

According to another aspect of the present invention, there is provided a mobile terminal establishing a dual connection with a first base station and a second base station, the mobile terminal comprising: a receiver for receiving higher layer signaling including retransmission request path information from a first base station; A control unit for generating a retransmission request status report for requesting retransmission of a data unit received from the second base station and a control unit for transmitting a retransmission request status report from the PDCP entity of the UE to the RLC entity of the UE peered to the RLC entity of the first base station Wherein the receiving unit receives a retransmission data unit requested through the retransmission request status report from the PDCP entity of the UE through the RLC entity of the UE paired with the RLC entity of the first base station.

In addition, the present invention provides a base station that forms a dual connection with a second base station together with a second base station, the base station including: a transmitter for transmitting upper layer signaling including retransmission request path information to the terminal; And a controller for transmitting a retransmission data unit from the PDCP entity of the base station to the RLC entity of the base station.

In addition, the present invention provides a dual access connection system comprising: a receiver for receiving upper layer signaling including retransmission path information from a first base station; And a control unit for transmitting a retransmission data unit to the RLC entity of the UE peered to the entity, wherein the receiving unit receives a retransmission request for requesting retransmission of a data unit not received from the first base station and the second base station in the PDCP entity of the UE A terminal device receiving the status report is provided.

In addition, the present invention provides a base station that forms a dual connection to a terminal together with a second base station, the base station comprising: a transmitter for transmitting upper layer signaling including retransmission path information to the terminal; A control unit for generating a retransmission request status report for retransmission and delivering the retransmission request status report to the RLC entity of the base station and a receiving unit for receiving the retransmission data unit requested through the retransmission request status report in the PDCP entity of the base station through the RLC entity of the base station Device.

According to the present invention, there is an effect of reducing a window stop problem in the process of reordering lost data by a terminal and a base station transmitting and receiving data by constituting a dual connection with a plurality of base stations.

In addition, there is an effect that the delay is reduced and the data is transmitted in order by constructing the double connection.

1 is a diagram illustrating an example of an uplink layer 2 structure in a carrier merging configuration.
2 is a diagram illustrating an example of a downlink layer 2 structure in a carrier merging configuration.
3 is a functional model of an RLC layer that may be configured in a terminal and a base station.
4 is a diagram illustrating an example of a network configuration scenario to which the present invention can be applied.
5 is a diagram showing another example of a network configuration scenario to which the present invention can be applied.
6 is a diagram illustrating another example of a network configuration scenario to which the present invention can be applied.
7 is a diagram illustrating an example of a layer 2 configuration of a terminal and a base station according to the present invention.
8 is a diagram illustrating another example of the layer 2 configuration of a terminal and a base station according to the present invention.
9 is a diagram illustrating a data transmission / reception procedure of a terminal and a base station in a downlink situation according to an embodiment of the present invention.
10 is a diagram illustrating an example of an RLC status PDU according to another embodiment of the present invention.
11 is a diagram illustrating an example of a CPT field value of an RLC PDU according to another embodiment of the present invention.
12 is a diagram illustrating an example of a D / C field value of an RLC PDU according to another embodiment of the present invention.
13 is a diagram illustrating operations of a UE in a downlink situation according to another embodiment of the present invention.
14 is a diagram illustrating the operation of a base station in a downlink situation according to another embodiment of the present invention.
15 is a diagram illustrating a data transmission / reception procedure of a terminal and a base station in an uplink situation according to another embodiment of the present invention.
16 is a diagram illustrating another embodiment of a layer 2 configuration of a terminal and a base station according to another embodiment of the present invention.
17 is a diagram illustrating an example of a PDCP status report according to another embodiment of the present invention.
18 is a diagram illustrating an example of a PDU type field value of a PDCP PDU according to another embodiment of the present invention.
19 is a diagram illustrating operations of a UE in an uplink situation according to another embodiment of the present invention.
20 is a diagram illustrating an operation of a base station in an uplink situation according to another embodiment of the present invention.
21 is a diagram illustrating a configuration of a UE in downlink and uplink situations according to another embodiment of the present invention.
22 is a diagram illustrating a configuration of a base station in downlink and uplink situations according to another embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference numerals whenever possible, even if they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The wireless communication system in the present invention is widely deployed to provide various communication services such as voice, packet data and the like. The wireless communication system includes a user UE (User Equipment) and an eNB (Base Station, BS, or base station). The term " user terminal " in this specification is a comprehensive concept of a terminal in a wireless communication, and includes a mobile station (MS), a user terminal (UT) (Subscriber Station), a wireless device, and the like.

An eNB or a cell is generally a station that communicates with a user terminal and includes a Node-B, an evolved Node-B, a sector, a site, a BTS A base transceiver system, an access point, a relay node, a remote radio head (RRH), a radio unit (RU), and the like.

That is, in this specification, the eNB or the cell is interpreted as a comprehensive meaning indicating a part or function covered by BSC (Base Station Controller) in CDMA, NodeB in WCDMA, base station or sector (site) in LTE, And covers various coverage areas such as megacell, macrocell, microcell, picocell, femtocell and relay node, RRH, and RU communication range.

Herein, the user terminal and the base station are used in a broad sense as the two transmitting and receiving subjects used to implement the technical or technical idea described in this specification, and are not limited by a specific term or word. The user terminal and the base station are used in a broad sense as two (uplink or downlink) transmitting and receiving subjects used to implement the technology or technical idea described in the present invention, and are not limited by a specific term or word. Here, an uplink (UL, or uplink) means a method of transmitting / receiving data to / from a base station by a user terminal, and a downlink (DL or downlink) .

There are no restrictions on multiple access schemes applied to wireless communication systems. Various multiple access schemes such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), OFDM-FDMA, OFDM- Can be used. An embodiment of the present invention can be applied to asynchronous wireless communication that evolves into LTE and LTE-Advanced via GSM, WCDMA, and HSPA, and synchronous wireless communication that evolves into CDMA, CDMA-2000, and UMB. The present invention should not be construed as limited to or limited to a specific wireless communication field and should be construed as including all technical fields to which the idea of the present invention can be applied.

A TDD (Time Division Duplex) scheme in which uplink and downlink transmissions are transmitted using different time periods, or an FDD (Frequency Division Duplex) scheme in which they are transmitted using different frequencies can be used.

In systems such as LTE and LTE-Advanced, the uplink and downlink are configured on the basis of one carrier or carrier pair to form a standard. The uplink and downlink transmit control information through a control channel such as a Physical Downlink Control Channel (PDCCH), a Physical Control Format Indicator CHannel (PCFICH), a Physical Hybrid ARQ Indicator CHannel (PHICH), and a Physical Uplink Control CHannel And a data channel such as a Physical Downlink Shared CHannel (PDSCH), a Physical Uplink Shared CHannel (PUSCH), and the like.

In this specification, a cell refers to a component carrier having a coverage of a signal transmitted from a transmission point or a transmission point or transmission / reception point of a signal transmitted from a transmission / reception point, and a transmission / reception point itself .

The wireless communication system to which the embodiments are applied may be a coordinated multi-point transmission / reception system (CoMP system) or a coordinated multi-point transmission / reception system in which two or more transmission / reception points cooperatively transmit signals. antenna transmission system, or a cooperative multi-cell communication system. A CoMP system may include at least two multipoint transmit and receive points and terminals.

The multi-point transmission / reception point includes a base station or a macro cell (hereinafter, referred to as a 'base station') and a base station, which is connected to the base station by an optical cable or an optical fiber and is wire- Lt; / RTI >

Hereinafter, a downlink refers to a communication or communication path from a multipoint transmission / reception point to a terminal, and an uplink refers to a communication or communication path from a terminal to a multiple transmission / reception point. In the downlink, a transmitter may be a part of a multipoint transmission / reception point, and a receiver may be a part of a terminal. In the uplink, the transmitter may be a part of the terminal, and the receiver may be a part of multiple transmission / reception points.

Hereinafter, a situation in which a signal is transmitted / received through a channel such as PUCCH, PUSCH, PDCCH, and PDSCH is expressed as 'PUCCH, PUSCH, PDCCH and PDSCH are transmitted and received'.

The base station performs downlink transmission to the UEs. The BS includes a Physical Downlink Shared Channel (PDSCH), which is a primary physical channel for unicast transmission, and downlink control information such as scheduling required for PDSCH reception and an uplink data channel A physical downlink control channel (PDCCH) for transmitting scheduling grant information for transmission in a Physical Uplink Shared Channel (PUSCH). Hereinafter, the transmission / reception of a signal through each channel will be described in a form in which the corresponding channel is transmitted / received.

Small cells using low power nodes are being considered as a means to cope with mobile traffic explosion. A low power node represents a node using lower transmit (Tx) power than a typical macro node.

Prior to 3GPP Release 11, Carrier Aggregation (hereinafter referred to as 'CA') technology has been proposed to provide a low output power RRH (Remote Radio), which is a geographically dispersed antenna within macrocell coverage with high output power. Head) can be used to build a small cell.

However, in order to apply the CA technology described above, the macro cell and the RRH cell are configured to be scheduled under one base station control, and an ideal backhaul is required between the macro cell node and the RRH.

An ideal backhaul refers to a backhaul that exhibits very high throughput and very little delay, such as a dedicated point-to-point connection using optical fiber, LOS microwave (Line Of Sight microwave).

In contrast, a backhaul exhibiting relatively low throughput and large delay, such as Digital Subscriber Line (xDSL) and Non-LOS microwave, is called a non-ideal backhaul.

The plurality of serving cells may be merged through the single base station based CA technology described above to provide services to the terminal. That is, a plurality of serving cells may be configured for a terminal in a state of a radio resource control (RRC) connected state, and when an ideal backhaul is established between the macro cell node and the RRH, RRH cells together constitute serving cells to provide services to the UE.

When a single base station based CA technology is configured, the terminal may only have one RRC connection with the network.

Access Stratum (hereinafter referred to as "NAS") mobility information (for example, TAI: information indicating the number of serving cells) in RRC connection establishment / re-establishment / Tracking Area Identity, and one serving cell provides a security input in RRC connection reset / handover. These cells are called PCell (Primary Cell). PCell can only be changed with the handover procedure. Depending on the capabilities of the terminals, SCells (Secondary Cells) can be configured as serving cells with PCells.

1 is a diagram illustrating an example of an uplink layer 2 structure in a single base station based carrier merging configuration.

In a single base station based carrier merger (CA), the multiple carrier properties of the physical layer only affected the MAC (Medium Access Control) layer. The MAC layer has one independent Hybrid Automatic Repeat reQuest (HARQ) entity for each serving cell in the uplink and downlink. Each HARQ entity processes the data stream of the component carrier (CC).

2 is a diagram illustrating an example of a downlink layer 2 structure in a carrier merging configuration.

Referring to FIGS. 1 and 2, a Packet Data Convergence Protocol (PDCP) layer operates on a Radio Link Control (RLC) layer. Each radio bearer (RB, e.g., DRB and SRB) is associated with one PDCP entity. Each PDCP entity is associated with one or two RLC entities (RLC entities) according to RB characteristics (i.e., unidirectional or bi-directional) and RLC mode. A PDCP entity is associated with a control plane or a user plane depending on the entity that carries it.

The Radio Link Control (RLC) layer is a layer that performs segmentation, concatenation, ARQ (Automatic Retransmission ReQuest), and the like. This function of the RLC layer is performed through an RLC entity.

For one RLC entity configured in the base station, an RLC entity is configured for peering. The RLC entity receives / delivers RLC SDUs (Service Data Units (SDUs)) from an upper layer to an upper layer, and transmits RLC entity / peer RLC entity (s) Quot; PDU "). The RLC entity transmits RLC data PDUs to a lower layer through a single logical channel.

Similar to the PDCP entity described above, one RLC entity may be configured to perform data transmission in one of three modes: Transparent Mode, Unacknowledged Mode (UM), or Acknowledged Mode (AM).

To briefly describe each mode, the RLC operating as TM transparently transmits the RLC SDUs received from the upper layer to the lower layer without adding any header information. The UM RLC can construct RLC PDUs by segmenting / concatenating RLC SDUs, and header information including the serial number is attached to each RLC PDU. UM operates in a non-response mode.

The RLC operating in AM performs error correction and re-segmentation through ARQ only for data transmission, and performs reordering only for AM and UM data transmission.

The reordering function is performed by maintaining the reordering window in the RLC entity. When the window is stalled, a new RLC data PDU can not be transmitted. The RLC window size usually uses half the value of the RLC SN (Sequence Number). The current RLC SN prevents HARQ data transmission, RLC feedback, and window stop due to retransmission of a lost RLC PDU, while minimizing the overhead of the RLC header. For the AM PDU, 5-bit or 10-bit values.

3 is a functional model of an RLC layer that may be configured in a terminal and a base station.

Referring to FIG. 3, the RLC layer receives an RLC SDU from an upper layer, performs segmentation and concatenation, and performs an ARQ function to transmit the generated RLC PDU to a lower layer. An RLC entity may forward an RLC PDU to a lower layer (e.g., MAC layer) over a logical channel.

The RLC PDUs transferred to the lower layer are transmitted to the UE or the BS through the MAC layer and the physical layer. In this case, it can be transmitted through the air interface.

As described above, in order to use the small cell using the carrier merging technique in the conventional mobile communication network, the macro cell and the small cell have to be scheduled under the control of one base station. For this purpose, an ideal backhaul between the macro cell node and the small cell node ideal backhaul). That is, when a macrocell and a small cell are constructed as individual base stations through a non-ideal backhaul, a plurality of carriers can not be effectively used due to a non-ideal backhaul delay.

Therefore, in order to effectively utilize a plurality of carriers in an environment in which macro cells and small cells are configured as individual base stations through non-ideal backhaul, it is necessary that individual base stations providing serving cells process MAC functions and RLC functions, There has been a problem that a window stop may occur in the process of performing the RLC reordering function due to a data transmission delay between RLC entities connected with non-ideal backhaul. There is a problem that window stalling may occur in the process of performing the PDCP reordering function due to a delay in data transmission between the RLC entity and the PDCP entity connected to the non-ideal backhaul.

In particular, when the PDCP entity of the macro cell BS constitutes a dual connection connected with the RLC entity of the macro cell BS and the RLC entity of the small cell BS, the data transmitted through the small cell BS is compared with the data transmitted through the macro cell BS And the non-ideal backhaul delay. Therefore, if the data mapped to one radio bearer is transmitted through two base stations, the PDCP layer, which must process data in sequence, frequently receives data out of order It is necessary to perform reordering in the PDCP layer.

When performing the reordering in the PDCP entity, the PDCP entity detects a missing PDCP data unit because the PDCP data unit can not be received until the reordering timer expires due to a radio link transmission loss or the like, the PDCP entity retransmits the missing PDCP data unit It was necessary to deliver a status report for the request and receive a retransmission data unit for the missing PDCP data unit via the peered PDCP entity. At this time, if the status report for the retransmission request for the missing PDCP data unit and the retransmission data unit for the missing PDCP data unit are transmitted through the cell / CC (Component Carrier) between the terminal and the small cell base station, And a non-ideal backhaul delay between the small cell base station and the small cell base station, there is a problem that a stoppage occurs or an unnecessary delay increases.

In order to solve such a problem, the present invention provides a method for controlling a macrocell and a small cell in a mobile communication network through a small cell under the control of a macrocell or in cooperation between a macrocell and a small cell To provide a method and apparatus for processing data transmitted through an individual base station while reducing the occurrence of a window stop, a data transmission and / or a processing delay in an RLC layer or a PDCP layer in transmitting data using a plurality of carriers do.

In this specification, a terminal establishes an RRC connection with a terminal, terminates a base station or an S1-MME that provides a PCell serving as a reference for handover, and performs a mobility anchor function with respect to the core network As a first base station.

The master base station may be a base station that provides macrocells, and may be a base station that provides any one small cell in the case of a dual connection between small cells. It may also be a base station providing PCell.

In addition, a secondary base station that provides additional radio resources to the terminal in a dual connection environment, which is distinguished from the master base station, is described as a second base station.

The first base station and the second base station may each provide at least one cell to the terminal, and the first base station and the second base station may be connected through an interface between the first base station and the second base station.

Unlike the above-described carrier merging technique, to which the present invention can be applied, a dual-link configuration network scenario in which base stations provide a plurality of serving cells to a UE in an environment of non-ideal backhaul between two base stations will be described.

4 is a diagram illustrating an example of a network configuration scenario to which the present invention can be applied.

Referring to FIG. 4, the macro cell 402 and the small cells 401 may have the same carrier frequency F1.

The first base station 410 providing the macro cell and the second base station 432, 434, 436 providing each small cell are connected via a non-ideal backhaul. The small cells are built in an overlaid macrocell 402 network. An outdoor small cell environment and a small cell cluster 401 can be considered.

A terminal can receive a plurality of serving cells through a double connection with a macro cell and a small cell in a small cell cluster 401.

5 is a diagram showing another example of a network configuration scenario to which the present invention can be applied.

Referring to FIG. 5, the macro cell 502 and the small cells 501 may have different carrier frequencies F1 and F2.

The first base station 510 providing the macro cell and the second base station 532, 534, 536 providing each small cell are connected through a non-ideal backhaul. The small cells are built in an overlaid macrocell 502 network. An outdoor small cell environment and a small cell cluster 501 can be considered.

A terminal may receive a plurality of serving cells through a double connection with a macro cell and a small cell in a small cell cluster 501. In this case, the frequencies of the respective serving cells may be different from each other by F1 and F2 as shown in Fig.

6 is a diagram illustrating another example of a network configuration scenario to which the present invention can be applied.

Referring to FIG. 6, a case where a plurality of small cells form a small cell cluster 601 can be considered. In this case, the small cell base stations 610, 612, and 614 providing the small cell are connected through a non-ideal backhaul. An indoor small cell environment and a small cell cluster 601 are considered.

The UE can transmit and receive data through a plurality of serving cells by forming a double connection with a plurality of small cell base stations.

In each example of the double connection configuration shown in FIGS. 4 and 5, the terminal may transmit control plane data through the first base station under the control of the first base station providing the macro cell.

Alternatively, the terminal may transmit control plane data through cooperation of a first base station and a second base station providing one or more small cells under the control of a first base station providing a macro cell.

Alternatively, in FIG. 6, the terminal may transmit control plane data through cooperation between a plurality of second base stations providing a small cell.

That is, in order to transmit the control plane data, the UE establishes an RRC connection with the first base station providing the macro cell, and may configure one or more Signaling Radio Bearers (SRBs) using only the radio resources of the first base station. Alternatively, for transmission of control plane data, the terminal may set up an RRC connection with a first base station providing a macrocell and one or more Signaling Radio Bearers (SRBs) using only the radio resources of the second base station. Alternatively, for transmission of control plane data, the UE establishes an RRC connection with a first base station providing a macro cell and establishes one or more Signaling Radio Bearers (SRBs) that simultaneously use the radio resources of the first and second base stations .

As another example, in each of the examples of the dual connection configuration shown in FIGS. 4 and 5, the UE transmits user plane data through a second base station providing one or more small cells under the control of a first base station providing a macro cell .

Alternatively, the terminal may transmit user plane data through the cooperation of a first base station and a second base station providing one or more small cells under the control of a first base station providing a macro cell.

Alternatively, in FIG. 6, the terminal may transmit user plane data through cooperation between a plurality of second base stations providing a small cell.

That is, in order to transmit the control plane data, the MS establishes one RRC connection with the first BS providing the macro cell and sets one or more DRBs (Data Radio Bearers) using only the radio resources of the first BS . Alternatively, for transmission of control plane data, the UE establishes an RRC connection with the first base station providing the macrocell, and may configure one or more DRBs (Data Radio Bearers) using only the radio resources of the second base station. Or control plane data transmission, the UE establishes one RRC connection with the first base station providing the macro cell, and one or more DRBs (Data Radio Bearers) that simultaneously use the radio resources of the first and second base stations. Can be set.

7 is a diagram illustrating an example of a layer 2 configuration of a terminal and a base station according to the present invention.

In other words, a layer 2 structure for transmitting data through one or more second base stations under the control of a first base station in accordance with the present invention, or through cooperation between a first base station and one or more second base stations, Respectively.

As shown in FIG. 7, the first base station and the second base station have RLC entities and MAC entities, respectively, for at least one radio bearer, and the PDCP entity can be configured only for the first base station.

The PDCP PDU of the first base station may be delivered to the RLC entity in the first base station. The RLC entity in the first base station and the RLC entity in the second base station are connected through the interface between the first base station and the second base station.

For the UE, one RLC entity can process the RLC function for at least one radio bearer.

That is, the RLC entity in the terminal can be peered to the RLC entity in the first base station and the second base station RLC entity to process the RLC function.

8 is a diagram illustrating another example of the layer 2 configuration of a terminal and a base station according to the present invention.

That is, another example of a layer 2 structure for transmitting data via one or more second base stations under the control of a first base station in accordance with the present invention, or through cooperation between a first base station and one or more second base stations Respectively.

Referring to FIG. 8, the first BS and the second BS may have RLC entities and MAC entities for at least one radio bearer, respectively, and the PDCP entity may be located only at the first BS.

The PDCP PDU of the first base station may be delivered to the RLC entity in the first base station. The RLC entity in the first base station and the RLC entity in the second base station are connected through the interface between the first base station and the second base station.

For at least one radio bearer, the terminal may process the RLC function through two RLC entities. That is, an RLC entity in the UE peered to the RLC entity in the first base station and an RLC entity in the UE peered to the RLC entity in the second base station can process the RLC function.

The PDCP PDU of the UE can be delivered to the RLC entity in the UE peered to the RLC entity in the first base station. The RLC entity in the UE peered to the RLC entity in the first base station and the RLC entity in the UE peered to the RLC entity in the second base station are internally connected.

Hereinafter, a method of transmitting and receiving data between a terminal and a base station according to each embodiment of the present invention will be described in detail.

7 and 8, a description will be made of a method for processing data transmission / reception between a terminal and a base station when a terminal according to an embodiment of the present invention is in a downlink state. The RLC entity described below operates in the AM mode.

One. AM RLC  Of the entity Downlink  Data processing method.

9 is a diagram illustrating a data transmission / reception procedure of a terminal and a base station in a downlink situation according to an embodiment of the present invention.

A method for processing data not received by a terminal constituting a dual connection with a first base station and a second base station according to an exemplary embodiment of the present invention includes receiving an upper layer signaling including retransmission request path information from a first base station Generating a retransmission request status report for retransmission of data units not received from the first base station and the second base station, and transmitting the retransmission request status report to the MAC entity of the terminal peered to the MAC entity of the first base station in the RLC entity of the UE And delivering a retransmission request status report. The RLC entity of the UE may receive the retransmission data unit requested through the retransmission request status report through the MAC entity of the UE peered to the MAC entity of the first base station.

A method for transmitting data by a Node B constituting a dual connection to a UE together with a second Node B according to another exemplary embodiment of the present invention includes transmitting an upper layer signaling including retransmission request path information to the UE, Receiving a retransmission request status report for requesting retransmission of a data unit not received from the terminal in the RLC entity of the RLC entity, and transmitting the retransmission data unit to the MAC entity of the base station.

Referring to FIG. 9, a terminal 901 configures a dual connection with a first base station 902 and a second base station 903. That is, the terminal 901 can transmit and receive data through the first base station 902 and the second base station 903, the first base station 902 is the above-described master base station serving as a mobility anchor, 2 base station 903 may be a secondary base station providing additional radio resources to the terminal 901. [

The terminal 901 receives the upper layer signaling including the retransmission request path information from the first base station 902 (S910). Or from the second base station.

The terminal 901 may receive the data unit through the cell associated with the first base station 902 and the second base station 903 (S915, S920).

Steps S910 and S915 and S920 may be performed in a different order.

The terminal 901 generates a retransmission request status report for requesting retransmission of the data unit received from the first base station 902 and the second base station 903 (S930).

Then, the UE 901 transmits a retransmission request status report to the MAC entity of the UE peered to the MAC entity of the first BS in the RLC entity. The MAC entity transmits a retransmission request status report through a cell or a component carrier (CC) associated with the first base station (S940).

The first base station 902 transmits a retransmission data unit to the MAC entity of the first base station based on the retransmission request status report received from the terminal 902 and the cell associated with the first base station and / Or transmits the retransmission data unit to the terminal through the CC (S950).

Through such a process, it is possible to prevent the occurrence of problems related to the window stop of the RLC entity or to reduce the data transmission and / or processing delay.

A method of transmitting and receiving data in the downlink situation of the present invention will be described concretely with reference to the drawings.

1) generating a data unit from the transmitting side of the RLC entity in the first base station and transmitting the data unit to the terminal;

Specifically, for example, when the transmitting side of the RLC entity in the first base station is generating Acknowledged Mode Data (AMD) PDUs from the RLC SDUs, the AMD PDUs are transmitted to the first base station Segmentation or concatenate to fit within the total size of the RLC PDU (s) indicated by the lower layer in the first base station to the specific transmission opportunity notified by the lower layer.

Alternatively, when the transmitting side of the RLC entity in the first base station is to create AMD PDUs to be transferred from the RLC SDUs to the lower layer in the first base station, the AMD PDUs may be associated with a particular transmission opportunity notified by a lower layer in the first base station (S) indicated by the lower layer in the first base station to fit within the total size of the RLC PDUs (s) indicated by the lower layer in the first base station.

Alternatively, when the transmitting side of the RLC entity in the first base station is to create AMD PDUs to be transferred from the RLC SDUs to the RLC entity in the second base station, the AMD PDUs are notified to the specific transmission The UE may segment and / or concatenate the opportunity (s) in consideration of the total size of the RLC PDUs (s) indicated by the lower layer in the first base station.

That is, the transmitting side of the RLC entity in the first base station considers the total size of the RLC PDUs indicated by the lower layer in the first base station to the specific transmission opportunity notified by the lower layer in the first base station or the second base station To perform segment and / or concatenation operations.

To this end, the first base station and the second base station may exchange information necessary for the segment and / or concatenate at the transmitting end of the RLC entity of the first base station. Or for this purpose, the first base station may receive the information needed to segment and / or concatenate at the transmitting end of the RLC entity of the first base station from the terminal.

Alternatively, when the transmitting side of the RLC entity in the first base station is to create AMD PDUs to be transferred from the RLC SDUs to the lower layer in the first base station, the AMD PDUs are notified to the specific transmission And / or concatenate to fit within the total size of the RLC PDUs (s) indicated by the lower layer in the first base station.

Also, when the transmitting side of the RLC entity in the first base station makes AMD PDUs to be transmitted from the RLC SDUs to the RLC entity in the second base station, the first base station and the second base station, considering the radio channel quality, interference, 2 base station to segment and / or concatenate AMD PDUs to be delivered to the RLC entity in the second base station.

For example, a segment and / or concatenate operation of AMD PDUs to be delivered to the RLC entity in the second base station described above may consistently segment and / or concatenate AMD PDUs.

For another example, segment and / or concatenate operations of AMD PDUs to be delivered to the RLC entity in the second base station may be segmented and / or concatenated by dynamically changing the size of the AMD PDUs .

For this purpose, the first base station and the second base station may exchange information necessary for segmenting and / or concatenating at the transmitting end of the RLC entity of the first base station. Or for this purpose, the first base station may receive the information needed to segment and / or concatenate at the transmitting end of the RLC entity of the first base station from the terminal.

When transmitting AMD PDUs on the transmitting side of the RLC entity in the first base station to the RLC entity in the second base station, the transmitting side of the RLC entity in the second base station is the transmitting side of the aforementioned AMD PDUs, Segmentation to fit within the total size of the RLC PDU (s) indicated by the lower layer to the particular transmission opportunity notified by the lower layer in the RLC PDU (s).

In the above, generation of a data unit for downlinking data from the base station to the terminal has been described briefly.

Hereinafter, the step of requesting the retransmission data unit by the terminal not receiving the data unit generated by the above method will be specifically described.

2) requesting retransmission of the data unit at the receiving side of the RLC entity in the terminal.

The receiving side of the AM RLC entity in the UE according to an exemplary embodiment of the present invention may reorder RLC data PDUs when RLC data PDUs are received out of sequence when receiving RLC data PDUs.

For example, when the receiving side of the AM RLC entity in the UE receives the RLC data PDUs, the receiving side of the AM RLC entity in the UE detects loss of the RLC data PDUs and requests retransmission to the peered AM RLC entity .

A UE according to an exemplary embodiment of the present invention may transmit a retransmission request status report to a first BS in order to request retransmission of a received RLC PDU.

The retransmission request status report may be any one of an RLC status PDU and an RLC control PDU.

Specifically, each case will be described with reference to the drawings.

First, the processing procedure when the above-mentioned retransmission status report is an RLC status PDU will be described.

10 is a diagram illustrating an example of an RLC status PDU according to another embodiment of the present invention.

The RLC entity in the terminal may transmit an RLC status PDU only through a macro cell or a radio link between the terminal and the first base station or between the terminal and the first base station CC or a cell associated with the first base station in order to reduce the occurrence of window stalling .

The aforementioned RLC status PDU is that the AM RLC entity transmits to the AM RLC entity that is peered to provide positive and / or negative acknowledgments of RLC PDUs (or portions of RLC PDUs).

When HARQ reordering of the RLC data PDUs associated with the UE is received or an RLC data PDU reception failure is detected (RLC reordering timer (t-reordering) expires) after the RLC data PDU whose polling field is set to 1 ).

The MS may determine that the RLC PDU is an RLC status PDU according to the value of the CPT field 1010 of the RLC PDU, and may transmit the MAC PDU or a cell associated with the MAC or the radio link between the MS and the first base station or the CC or the first base station.

That is, in order for the UE to transmit the RLC status PDU only through the macrocell or the radio bearer (or carrier) between the UE and the first base station, the RLC entity in the UE transmits a Control PDU Type field 1010 of the RLC PDU When the RLC PDU is set to the status PDU value (000), the RLC status PDU may be transmitted to a MAC cell or a lower layer (MAC entity) associated with a radio bearer (or carrier) between the UE and the first BS.

11 is a diagram illustrating an example of a CPT field value of an RLC PDU according to another embodiment of the present invention.

Referring to FIG. 11, the UE determines a corresponding RLC PDU as an RLC status PDU according to a CPT field value of an RLC PDU, and transmits the RLC PDU to a macro cell or a cell associated with a CC or a first base station through a radio link between the UE and the first base station .

That is, if the 3-bit CPT (Control PDU Type) field value of the RLC PDU shown in FIG. 10 is set to '000', the RLC entity in the UE detects the RLC status PDU and transmits the RLC status PDU to the first cell To a CC between base stations or to a cell associated with a first base station or to a lower layer (MAC entity) associated with a first base station.

In another method, a method for transmitting an RLC Control PDU to a UE through a macro link or a radio link between the UE and the first BS or between a BS and a first BS or a cell associated with the first BS will be described.

The RLC entity in the UE transmits a 1-bit Data / Control (D / C) message of the RLC PDU in order to allow the MS to transmit the RLC Control PDU only through a macro cell or a cell link between the MS and the first BS, ) Field is set to a Control PDU value (0), the above-described RLC Control PDU is transmitted to the cell associated with the macro cell or between the MS and the first base station or the cell associated with the first base station or the lower layer (MAC entity).

12 is a diagram illustrating an example of a D / C field value of an RLC PDU according to another embodiment of the present invention.

Referring to FIG. 12, when the value of the D / C field of the RLC PDU is '0', the UE detects the corresponding PDU as an RLC control PDU and transmits the RLC control PDU to the macro cell or the CC To a cell associated with one base station or a lower layer (MAC entity) associated with the first base station.

As described above, the MS of the present invention can reduce the occurrence of the window suspension problem of the RLC entity by allowing the MS to transmit the retransmission request status report to the macro cell or the first BS through the cell associated with the CC or the first BS. Or to reduce the data delay.

The UE according to another embodiment of the present invention can receive the upper layer signaling including the retransmission request path information from the first base station.

In addition, the retransmission request path information of the present invention may include information for setting a retransmission request status report to be transmitted through the cell and / or the CC associated with the first base station.

As described above, the RLC status PDU or the RLC Control PDU of the radio bearer mapped to the AM RLC is transmitted through the first base station or the macro cell (PCell) or a radio link between the UE and the first base station or a cell associated with the CC or the first base station Information is transmitted to the terminal through higher layer signaling.

For example, the retransmission request path information may set information for operating the above-described functions in an RRC message (for example, rlc-config information in a RadioResourceConfigDedicated information element in an RRC Connection Reconfiguration message) and transmit the information to the terminal.

Alternatively, the retransmission request path information may be set by defining new information in the RadioResourceConfigDedicated information element of the RRC message (for example, an RRC Connection Reconfiguration message) and may be transmitted to the UE, When configuration information is included, it can be applied by default.

Accordingly, the UE transmits the RLC status PDU or the RLC control PDU to the macro cell or the radio link between the UE and the first base station or the CC or the first base station, based on the retransmission request path information included in the higher layer signaling received from the first base station. Lt; RTI ID = 0.0 > cell < / RTI >

7 or 8, the UE transmits an RLC status PDU or an RLC Control PDU of a radio bearer mapped to the AM RLC to a first base station or a macro cell (PCell) or a radio link or a CC Or through a cell associated with the first base station.

3) A method for transmitting a retransmission data unit at a transmitting side of an RLC entity in a first base station.

The first base station according to another embodiment of the present invention can retransmit the corresponding data unit upon receiving the above-mentioned retransmission request data unit from the terminal.

In this case as well, a macro cell or a radio link between the terminal and the first base station or a cell associated with the CC or the first base station is transmitted as described above.

Specifically, for example, a transmitting side of an AM RLC entity in a first base station may receive, from an AM RLC entity in the UE, one AMD PDU or a portion of an AMD PDU via an RLC status PDU a negative acknowledgment may be received.

When a negative acknowledgment is received for one AMD PDU or a portion of one AMD PDU by the RLC status PDU from the peered AM RLC entity as described above, the transmitting side of the AM RLC entity performs retransmission.

In this case, the RLC entity in the first base station transmits an AMD PDU, which has received a negative acknowledgment to reduce window stalling, to a macrocell or a wireless link between the terminal and the first base station, Or only through a cell associated with the first base station.

That is, the RLC entity in the first base station forwards the AMD PDU that received the negative acknowledgment to the lower layer (MAC entity) in the first base station to reduce the occurrence of window stalling.

The first base station according to another embodiment of the present invention transmits the retransmission data unit only through a macro cell or between a first base station and a terminal via a radio link or a cell associated with the CC or the first base station, But only through a radio link associated with the first base station or a cell associated with the CC or the first base station. That is, the AMD PDU of the retransmission buffer can be transmitted only to a lower layer (MAC entity) in the first base station.

Also, when the first base station desires to transmit the above-described RLC control PDU from the terminal, the first base station may transmit the RLC control PDU through the cell associated with the macro link or the CC or the first base station, have.

The operation of the terminal will be described with respect to the present invention specifically described above.

13 is a diagram illustrating operations of a UE in a downlink situation according to another embodiment of the present invention.

A method for processing data not received by a UE constituting a dual connection with a first base station and a second base station according to another embodiment of the present invention includes the steps of receiving upper layer signaling including retransmission request path information from a first base station Generating a retransmission request status report for requesting retransmission of a data unit received from a first base station and a second base station, and transmitting a retransmission request status report through a radio cell and / or a CC associated with the first base station And receiving a retransmission data unit via the radio cell and / or the CC associated with the first base station.

Referring to FIG. 13, a UE receives an upper layer signaling including retransmission request path information from a first base station (S1310).

As described above, the higher layer signaling may be an RRC message, for example, an RRC Connection Reconfiguration message.

The retransmission request path information may include information for setting a retransmission request status report to be transmitted via the cell and / or the CC associated with the first base station.

The terminal may receive a data unit from each of the dual-connected first base station and the second base station and may request retransmission of a lost or corrupted data unit of the received data unit.

Therefore, the terminal generates a retransmission request status report for the retransmission request (S1320). As described above, the retransmission request status report may be an RLC status PDU or an RLC control PDU. The value of the CPT field may be set to '000' and the value of the D / C field of the RLC control PDU may be set to '0'.

The MS can transmit the generated retransmission request status report to the macro cell or the cell associated with the CC or the first BS through the radio link between the first BS and the MS (S1330).

After transmitting the retransmission request status report, the UE can receive the retransmission data unit through the cell associated with the first base station or the macro cell or the wireless link between the UE and the first base station or the CC or the first base station (S1340).

The UE can transmit and receive the retransmission request status report and the retransmission data unit only through the wireless link between the UE and the first base station or the cell associated with the CC or the first base station, thereby solving the problem caused by the window stop and reducing the data delay .

Hereinafter, the operation of the base station will be described.

14 is a diagram illustrating the operation of a base station in a downlink situation according to another embodiment of the present invention.

A method for transmitting data by configuring a dual connection to a terminal together with a second base station according to another embodiment of the present invention includes transmitting an upper layer signaling including retransmission request path information to the terminal, Receiving a retransmission request status report via the cell and / or the CC associated with the base station, and transmitting the retransmission data unit through the cell and / or the CC associated with the base station to the terminal.

Referring to FIG. 14, a BS may transmit an upper layer signaling and data unit including retransmission request path information to a UE (S1410).

As described above, the retransmission request path information may include configuration information for allowing a terminal to transmit a retransmission request status report only through a radio link between the base station and the terminal or only through a cell associated with the CC or the first base station, and may be transmitted through the RRC message. have.

The base station receives a retransmission request status report from the terminal through a radio link between the terminal and the base station or through a cell associated with the CC or the first base station (S1420).

The base station retransmits the retransmission data unit included in the retransmission request status report to the terminal (S1430). In this case, the retransmission data unit may only be transmitted via a macro link or a radio link between the terminal and the base station, or a cell associated with the CC or the first base station.

To this end, the terminal may set the data contained in the retransmission buffer to be transmitted only through a radio link associated with the base station or a cell associated with the CC or the first base station.

In the foregoing, the case where the terminal downlinks data has been described in an embodiment of the present invention.

Hereinafter, a transmission / reception processing method in a case where a terminal according to another embodiment of the present invention transmits data uplink to a base station will be described with reference to the hierarchical structure of FIG. 7 and FIG.

2. AM RLC  Of the entity Uplink  Data processing method.

15 is a diagram illustrating a data transmission / reception procedure of a terminal and a base station in an uplink situation according to another embodiment of the present invention.

A method for transmitting data by establishing a dual connection with a first base station and a second base station according to another embodiment of the present invention includes receiving a higher layer signaling including retransmission path information from a first base station, Transmitting a data unit to a first base station and a second base station, receiving a retransmission request status report for retransmission of a lost data unit through a cell and / or a CC associated with the first base station, And transmitting the retransmission data unit via the cell and / or the CC.

A method for processing data not received by constructing a dual connection with a second base station in a base station according to another embodiment of the present invention includes transmitting upper layer signaling including retransmission path information to the terminal And generating a retransmission request status report for retransmission of the lost data unit received from the terminal and transmitting a retransmission request status report via the radio cell and / or CC associated with the base station and the cell associated with the base station and / And receiving the retransmission data unit via the CC.

Referring to FIG. 15, a terminal 1501 forms a dual connection with a first base station 1502 and a second base station 1503.

The terminal 1501 receives the upper layer signaling including the retransmission path information from the first base station (S1510). The retransmission path information may include information to set the retransmission data unit to be transmitted via the cell and / or the CC associated with the first base station. That is, the RLC layer of the UE transmits the requested retransmission data unit through the retransmission request status report of the first BS to the MAC entity of the UE peered to the MAC entity of the first BS, or transmits a retransmission request Information to set the requested retransmission data unit through the status report to be transmitted through the cell and / or the CC associated with the first base station.

The retransmission path information may be defined as information elements such as the retransmission request path information, and may be defined as information elements other than the retransmission request path information. For example, if the retransmission request path information and the retransmission path information are defined as one information element (for example, retransmissionpath = MeNB) and the information element is included in the RRC message, the retransmission request status report and the retransmission data unit All through the cell and / or CC associated with the first base station.

As another example, if one or more of the above-described information elements is included in the RRC message by defining the retransmission request path information and the retransmission path information as other information elements (for example, stautsreportpath = MeNB, dataretransmissionpath = MeNB) And the corresponding retransmission data units may be transmitted via the cell and / or the CC associated with the first base station, respectively.

The UE 1510 may transmit data units to the first base station 1502 and the second base station 1503 through a dual-connected radio bearer (S1515, S1520).

Steps S1510 and S1515 and S1520 may be performed in a different order.

The first base station 1502 generates a retransmission request status report for requesting retransmission of the data unit if loss and / or damage to the received data unit occurs (S1530). As with the downlink, the retransmission request status report can be either an RLC status PDU or an RLC control PDU.

The first base station 1502 transmits the generated retransmission request status report to the macrocell or the terminal 1501 through the cell associated with the CC or the first base station between the terminal and the first base station (S1540).

The UE 1501 receives the retransmission request status report and transmits the lost retransmission data unit included in the retransmission request status report through a radio link between the first BS and the MS or a cell associated with the CC or the first BS S1550).

The data transmission / reception method in the uplink situation of the present invention will be described concretely with reference to the drawings in each step.

1) a segmentation / concatenation step for the generation of a data unit on a transmitting side of an RLC entity in a terminal;

The transmitting side of the RLC entity in the terminal is configured to determine the total size of the RLC PDUs (s) indicated by the lower layer at a particular transmission opportunity notified by the lower layer when AMD PDUs are created from the RLC SDUs. / RTI > and / or concatenate to fit within the first and second regions.

The UE transmits the generated RLC PDU through the first BS and / or the second BS.

2) Send a retransmission request status report on the receiving side of the RLC entity in the first base station.

The first base station receiving the data unit from the terminal can transmit a retransmission request status report for retransmission when a loss or a corruption occurs in the data unit.

The first base station according to an embodiment of the present invention may transmit only the cell or the CC or the cell associated with the first base station between the terminal and the first base station when transmitting the retransmission request status report.

Specifically, for example, when the first base station receives the RLC data PDUs, the receiving side of the AM RLC entity in the first base station transmits the RLC data PDUs to the RLC data PDUs when the RLC data PDUs are received out- can do.

Alternatively, when the receiving side of the AM RLC entity in the first base station receives the RLC data PDUs, the receiving side of the AM RLC entity in the first base station detects the loss of the RLC data PDUs and retransmits them to the peered AM RLC entity .

As described above, the retransmission request status report may be an RLC status PDU or an RLC control PDU.

When the retransmission request data unit is an RLC status PDU, the RLC entity in the first base station transmits an RLC status PDU to the macro cell or the radio link between the first base station and the terminal or the CC or the first base station To be transmitted only through the cell associated with the base station.

10 and 11, an RLC status PDU is transmitted to an AM RLC entity that has been peered to provide positive and / or negative acknowledgments of RLC PDUs (or portions of RLC PDUs) When receiving an RLC data PDU with a polling field set to 1 after HARQ reordering of associated RLC data PDUs or detecting a failure to receive an RLC data PDU (RLC reordering timer (t-reordering) expires ).

In order for an RLC entity in a first base station to transmit an RLC status PDU only through a macrocell or a cell between a first base station and a terminal or a cell associated with a CC or a first base station, the RLC entity in the first base station transmits three bits When the RLC PDU value is set to the status PDU value (000) through the CPT (Control PDU Type) field, the RLC status PDU is transmitted to the macro cell or the cell link between the first base station and the UE / To a lower layer (MAC entity) associated with the first base station.

Alternatively, in order for the RLC entity in the first base station to transmit the RLC Control PDU only through the macrocell or cell between the first base station and the terminal or over a cell associated with the CC or the first base station, the RLC entity in the first base station transmits an RLC When the RLC PDU is set to the Control PDU value (0) through the 1-bit Data / Control (D / C) field of the PDU, (MAC entity) associated with a cell / first base station associated with one base station. Specific methods are the same as those described in Figs.

3) Transmitting retransmission data units at the transmitting side of the RLC entity in the terminal.

The MS may receive the retransmission request status report and transmit the retransmission data unit to the macro cell or the first BS through the radio cell / CC configured between the MS and the UE.

Specifically, for example, a transmitting side of an AM RLC entity in a UE transmits a negative acknowledgment (ACK) for a single AMD PDU or a portion of an AMD PDU through an RLC status PDU from an AM RLC entity in the UE (acknowledgment).

When a negative acknowledgment is received for one AMD PDU or a portion of one AMD PDU by the RLC status PDU from the peered AM RLC entity as described above, the transmitting side of the AM RLC entity performs retransmission.

In this case, the RLC entity in the UE may transmit an AMD PDU received a negative acknowledgment to the macro cell or a radio link between the mobile station and the first base station or a CC or the first base station between the mobile station and the first base station in order to reduce the occurrence of window stalling. Lt; RTI ID = 0.0 > 1 < / RTI > base station.

That is, the RLC entity in the UE transmits an AMD PDU received a negative acknowledgment to the macrocell or the first base station or the radio link between the UE and the first base station / CC / first base station to reduce the occurrence of window stalling To the lower layer (MAC entity) associated with the associated cell / first base station.

The UE according to another embodiment of the present invention may be configured to transmit the retransmission data unit in such a manner that the data included in the retransmission buffer is transmitted only through the radio link associated with the first base station or the cell associated with the CC or the first base station have.

That is, the AMD PDU of the retransmission buffer can be set to be transmitted only to the lower layer (MAC entity) in the first base station in order to transmit the retransmission data unit only through the radio bearer associated with the first base station.

In order to set the transmission path of the retransmission data unit described above, the first base station or the second base station transmits upper layer signaling including retransmission path information to the terminal.

Specifically, for example, if an RLC data PDU having received a negative acknowledgment through an RLC status PDU of a radio bearer mapped to an AM RLC is transmitted to a first BS or a macro cell (PCell) or a radio link CC or the cell associated with the first base station in the RRC message (for example, the rlc-config information in the RadioResourceConfigDedicated information element in the RRC Connection Reconfiguration message) and transmit the information to the UE.

Alternatively, when new information is defined in the RRC message (for example, new information is used in the RadioResourceConfigDedicated information element of the RRC Connection Reconfiguration message) and the radio resource is configured as shown in FIG. 7 or 8, the UE transmits the AMR- (RLC) PDU received via a RLC status PDU to a first base station or a macro cell (PCell) or a cell associated with a radio link between a terminal and a first base station or a CC or a first base station have.

Alternatively, an RLC data PDU received a negative acknowledgment through an RLC status PDU of a radio bearer mapped to an AM RLC may be transmitted to a first BS or a macro cell (PCell) or a radio link between the UE and the first BS, The information to be transmitted through the cell associated with the first base station may include an RLC status PDU or an RLC Control PDU of a radio bearer mapped to the AM RLC as described above to a first base station or a macro cell (PCell) Or information to be transmitted via the CC or a cell associated with the first base station.

The RLC entity in the first base station and the RLC entity in the second base station are connected through the interface between the first base station and the second base station with respect to the radio bearer mapped to the AM RLC as shown in FIG. Or between the first base station and the second base station between the PDCP entity in the first base station and the RLC entity in the second base station for the radio bearer mapped to the AM RLC as shown in FIG.

The GTP tunnel may use the TCP protocol or the SCTP protocol instead of the UDP protocol as the transport layer protocol in order to guarantee the in-sequence transmission of the interface between the first base station and the second base station through the interface described above with the non-ideal backhaul have. To this end, the first base station may include the above-described transport layer protocol information in a signaling message for establishing a radio bearer via the second base station.

Another way to ensure in-sequence transmission for a radio bearer mapped to an AM RLC is to provide a method for ensuring in-sequence transmission between the RLC entity in the first base station and the RLC entity in the second base station, or between the PDCP entity in the first base station and the second base station (E.g., status reporting) to provide flow control or ARQ (Automatic Repeat reQuest) between RLC entities.

In the above description, when the UE transmits uplink data to the BSs, the retransmission request status report of the UE and the BS and the transmission path of the retransmission data unit have been described in detail, for example.

Hereinafter, another example in which the present invention is applied to another hierarchical structure will be described.

16 is a diagram illustrating another embodiment of a layer 2 configuration of a terminal and a base station according to another embodiment of the present invention.

Figure 16 is a block diagram of another embodiment of a Layer 2 architecture for transmitting data via one or more second base stations under the control of a first base station in accordance with the present invention or through cooperation between a first base station and one or more second base stations FIG.

Referring to FIG. 16, a first BS and a second BS may have an RLC entity and a MAC entity for at least one radio bearer, respectively, and the PDCP entity may be located only at the first BS.

In this case, the PDCP PDU of the first base station may be delivered to the RLC entity in the first base station and the RLC entity in the second base station. The PDCP entity in the first base station and the RLC entity in the second base station are connected through an interface between the base stations.

The UE can process the RLC function through the two RLC entities for the dual-connected radio bearer using the radio resources of the first and second base stations simultaneously.

That is, the RLC entity can process the RLC function through the RLC entity in the UE peered to the RLC entity in the first base station and the RLC entity in the UE peered to the RLC entity in the second base station.

The PDCP PDU of the UE can be delivered to the RLC entity in the UE peered to the RLC entity in the first base station and the RLC entity in the UE peered to the RLC entity in the second base station.

In the case of dual-connected terminals and base stations configured as shown in FIG. 16, retransmission requests for lost data and retransmission of lost data can be performed in the PDCP layer.

That is, when the PDCP entity of the first base station configures a dual connection in which the RLC entity of the first base station and the RLC entity of the second base station are connected as shown in FIG. 16, data transmitted through the second base station is transmitted through the first base station And includes a non-ideal backhaul delay relative to the transmitted data. Therefore, if data belonging to one radio bearer is transmitted through two base stations, it is possible to receive out-of-order data frequently in the PDCP layer, which needs to process data in sequence, so that re- There is a need to do. When performing the reordering in the PDCP entity, the PDCP entity detects a missing PDCP data unit because the PDCP data unit can not be received until the reordering timer expires due to a radio link transmission loss or the like, the PDCP entity retransmits the missing PDCP data unit It must deliver a status report for the request and receive the retransmission data unit for the missing PDCP data unit via the peered PDCP entity. At this time, if a status report for requesting retransmission of a missing PDCP data unit and a retransmission data unit for a missing PDCP data unit are transmitted through a cell / CC (Component Carrier) between the UE and the small cell BS, A non-ideal backhaul delay between the first base station and the second base station may cause a stoppage or an unnecessary delay in the process of processing the reordering.

The invention according to another embodiment of the present invention can perform a retransmission process in the same manner as described in the above-described structures of FIGS. 7 and 8.

However, under the hierarchical structure of FIG. 16, the retransmission request status report may be a PDCP status report, and the retransmission data unit may be a user plane PDCP PDU.

The PDCP status report which can be one of the retransmission request status reports under the hierarchical structure as shown in FIG. 16 according to another embodiment of the present invention will be described.

Specifically, for example, a window stalling is performed in the PDCP layer for a radio bearer mapped to AM RLC, in the same manner as the retransmission request for the lost data of the RLC layer described above under the structure of FIG. 7 and FIG. 8, A retransmission request (e.g., a PDCP status report) for lost data to reduce the occurrence or to reduce data transmission and / or processing delays may be generated between a macrocell or a wireless link between the terminal and the first base station or between the terminal and the first base station CC or only the cell associated with the first base station.

17 is a diagram illustrating an example of a PDCP status report according to another embodiment of the present invention.

17, when the PDCP PDU is set to a PDCP status report value through the 3-bit PDU type field 1710, the PDCP entity transmits the PDCP status report to the macro cell or the CC or the first base station To a cell associated with one base station or a lower layer (RLC entity) associated with the first base station.

Alternatively, the above-described PDCP status report value may use the PDCP status report value (000) selectively used for handover, and the format of the PDCP status report frequently occurring according to the dual connection may be used in a conventional handover May be different from the PDCP status report format selectively used. In this case, one value may be newly designated and used in the currently reserved bit value (010-111). Even when the format of the PDCP status report frequently occurring according to the dual connection is different from that of the PDCP status report format selectively used according to the conventional handover, the PDCP status report value (000) You can also use the same value.

18 is a diagram illustrating an example of a PDU type field value of a PDCP PDU according to another embodiment of the present invention.

Referring to FIG. 18, when the PDU type field of the PDCP PDU is set to 000, the PDCP entity detects the corresponding PDU as a PDCP status report, and detects a radio link between the terminal and the first base station, Lt; RTI ID = 0.0 > cell. ≪ / RTI >

Alternatively, in order to allow the PDCP entity to quickly process other PDCP control data (e.g., PDCP Control PDUs for interspersed ROHC feedback packets) and / or control plane PDCP Data PDUs, other PDCP control data PDCP PDCP Data PDU to be transmitted only through a macro-cell or a radio link between the UE and the first base station or between the UE and the first base station CC or a cell associated with the first base station . To this end, when the PDCP PDU is set to the Control PDU value (0) or the PDCP PDU starts with the R (Reserved) bit through the Data / Control (D / C) field of the PDCP PDU, the PDCP entity distinguishes the PDCP PDU Control PDU and / or control plane PDCP Data PDU to a macrocell or cell between the terminal and the first base station or to a cell associated with the first base station or a lower layer (RLC entity) associated with the first base station.

The UE or the first base station retransmits the lost PDCP PDUs (PDCP PDUs) in the PDCP layer to the RBs mapped to the AM RLC in the same manner as the retransmission of the lost data of the RLC layer described above under the structure of FIG. 7 or 8 The retransmission data unit included in the request status report and the retransmission request status report may be transmitted only through the macrocell or the wireless link between the terminal and the first base station or only between the terminal and the first base station CC or the cell associated with the first base station.

To this end, when a negative acknowledgment is received by the PDCP status report, the terminal or the PDCP entity of the first base station performs retransmission. For example, when the PDCP status report uses a conventional PDCP status report that is selectively used in handover, the PDCP SN of the first missing PDCP SDU is referred to as a first missing PDCP SN (FMS) Field. For the missing PDCP SDU, the bit position of the Bitmap field is set to zero. That is, the PDCP SN is set to 0 (FMS + bit position) modulo (Maximum PDCP SN + 1). For the PDCP status report and / or the missing PDCP PDU described above, the terminal or the PDCP entity of the first base station may communicate with the macrocell or terminal in order to reduce the occurrence of window stalling or reduce data transmission and / And only through a radio link between the base stations or a cell associated with the terminal and the first base station CC or the first base station.

That is, the PDCP entity of the terminal or the first base station may transmit the PDCP status report and / or the missing PDCP data unit to the macrocell or terminal in order to reduce window stalling occurrence or reduce data transmission and / The CC between the base stations or the cell associated with the first base station is transmitted to the lower layer (RLC entity) associated with the first base station.

For example, the PDCP entity of the UE may transmit a retransmission request status report to the RLC entity of the UE peered to the RLC entity of the first BS. The PDCP entity of the first base station transmits the missing PDCP data unit requested by the PDCP entity of the UE through the retransmission request status report through the RLC entity of the first base station and transmits the radio link or the first The PDCP entity of the UE can receive the retransmission data unit through the RLC entity of the UE peered to the RLC entity of the first base station by allowing the PDCP entity of the UE to transmit through the cell between the BS and the BS.

In another example, in receiving a retransmission request status report for requesting retransmission of a data unit that has not been received from the first base station and the second base station in the PDCP entity of the UE, when the PDCP entity of the first base station receives an RLC Entity to transmit a retransmission request status report and to transmit through a radio link between the terminal and the first base station or a cell between the terminal and the first base station CC or a cell associated with the first base station. The RLC entity of the UE peered to the RLC entity of the first base station in the PDCP entity of the UE receives the retransmission request status report through the RLC entity of the UE in the PDCP entity of the UE, The PDCP data unit included in the retransmission request status report may be transmitted to be transmitted through a radio link between the subscriber station and the first base station or a cell associated with the first base station CC or the first base station.

For example, the data unit included in the retransmission buffer of the PDCP entity of the UE may be configured to be transmitted only to the RLC entity of the UE peered to the RLC entity of the first base station. As another example, the data unit included in the retransmission buffer of the PDCP entity of the first base station may be configured to be transmitted only to the RLC entity of the first base station

As described above, a retransmission request status report or a PDCP Control PDU or a PDCP PDU for retransmission mapped to an AM RLC is transmitted to a first BS or a macrocell (PCell) or a radio bearer (or carrier) between the UE and the first BS Information can be transmitted through higher layer signaling.

For example, information for operating the above-described functions may be set in an RRC message (for example, pdcp-config information or rlc-config information in a RadioResourceConfigDedicated information element in an RRC Connection Reconfiguration message) and transmitted to the terminal. At this time, the retransmission request status report to transmit the above-described retransmission request status report only through the radio link between the UE and the first base station or between the UE and the first base station CC or the cell associated with the first base station, and the above- The retransmission path information for transmitting the included missing PDCP data unit only through the radio link between the terminal and the first base station or between the terminal and the first base station CC or the cell associated with the first base station may be defined as the same information element, May be defined as information elements other than the above-mentioned retransmission request path information.

For example, if the retransmission request path information and the retransmission path information are defined as one information element (e.g., retransmissionpath = MeNB) and the information element is included in the RRC message, the retransmission request status report and the retransmission data unit All through the cell and / or the CC associated with the first base station. As another example, if one or more of the above information elements are included in the RRC message by defining the retransmission request path information and the retransmission path information as other information elements (for example, stautsreportpath = MeNB, dataretransmissionpath = MeNB), a retransmission request status report The retransmission data units may each be transmitted via a cell and / or a CC associated with the first base station. In another method, new configuration information for a radio resource configuration as shown in FIG. 16 is included in an RRC message (for example, new information is used for a RadioResourceConfigDedicated information element of an RRC Connection Reconfiguration message) (for example, 1 RLC entity of the first base station and RLC entity of the second base station). When a radio resource is configured as shown in FIG. 16, the UE transmits a PDCP Status report or PDCP Control PDU of the radio bearer mapped to the AM RLC, A PDCP PDU for retransmission may be transmitted through a cell associated with a first base station or a macro cell (PCell) or a wireless terminal between the terminal and the first base station and between the first base station CC or the first base station.

Operations of other terminals and base stations are performed in the same manner as described with reference to FIG. 9 and FIG.

As described above, according to the present invention, in a mobile communication network, a macro cell and a small cell are constructed through a separate base station through a non-ideal backhaul, under the control of a first base station providing a macro cell, It is possible to reduce the occurrence of a window stop in the PDCP layer in transmitting data through cooperation between the second base stations or to process data transmitted and received through individual base stations while reducing data transmission and / or processing delay.

The case where the present invention operates under the hierarchical structure of FIG. 16 has been described above. Operations of the other terminal and the base station can be performed similarly to those described in Figs. 9 and 15. Fig. Therefore, the specific operation of the case where the terminal transmits the retransmission data unit to the base station during the downlink and uplink operations of the terminal and the base station (uplink) will be described below with reference to the drawings. Operations in the downlink situation are the same as those described in Figs. 13 and 14 except for some differences described above.

19 is a diagram illustrating operations of a UE in an uplink situation according to another embodiment of the present invention.

A method for transmitting data between a first terminal and a second terminal, the method comprising: receiving an upper layer signaling including retransmission path information from a first base station; Receiving a retransmission request status report for requesting retransmission of a data unit that has not been received from the first base station and the second base station in a PDCP entity of the UE and receiving a retransmission request status report from the RCP entity of the UE peered to the RLC entity of the first base station, And delivering the retransmission data unit to the entity.

Referring to FIG. 19, the MS receives an upper layer signaling including retransmission path information from the first BS (S1910).

The retransmission path information may include information for setting the retransmission data unit to be transmitted via the cell / CC associated with the first base station.

For example, the retransmission path information may include information for setting a retransmission data unit requested by the PDCP entity of the UE through the retransmission request status report of the first BS to be delivered to the RLC entity of the UE peered to the RLC entity of the first BS, And information for setting the retransmission data unit to be transmitted through the cell or a component carrier (CC) associated with the first base station through the terminal's retransmission request status report of the first base station. have.

A PDCP entity of the UE receives a retransmission request status report for requesting retransmission of a data unit not received from the first BS and the second BS,

The terminal receives the retransmission request status report from the first base station through the cell associated with the first link, the CC or the first base station between the first base station and the terminal (S1920). For example, a PDCP entity of the UE receives a retransmission request status report for requesting retransmission of data units not received from the first and second base stations.

The MS transmits the retransmission data unit included in the retransmission request status report to the first BS (S1930). In this case, the retransmission data unit may only be transmitted between the macrocell or the terminal and the first base station via the radio link or the CC or the cell associated with the first base station.

20 is a diagram illustrating an operation of a base station in an uplink situation according to another embodiment of the present invention.

A method for processing data not received by a base station having a dual connection with a second base station according to another exemplary embodiment of the present invention includes the steps of transmitting upper layer signaling including retransmission path information to a terminal, Generating a retransmission request status report for requesting retransmission of data units not received from the UE in the PDCP entity of the base station, transmitting a retransmission request status report to the RLC entity of the base station in the PDCP entity of the base station, And receiving the requested retransmission data unit via the RLC entity of the base station through the retransmission request status report.

Referring to FIG. 20, a BS generates an upper layer signaling including retransmission path information including information on a transmission path of a retransmission data unit of a UE, and transmits the upper layer signaling to the AT (S2010). As described above, the upper layer signaling may be an RRC Connection Reconfiguration message.

The PDCP entity of the base station detects loss or damage to the data unit received from the terminal and generates a retransmission request status report for requesting retransmission of the corresponding data unit that has not been received due to loss or corruption in operation S1820.

The BS transmits the generated retransmission request status report to the macro cell or the BS through the cell associated with the CC or the BS (S2030). As described above, the above-described retransmission request status report is transmitted from the PDCP entity of the base station to the RLC entity of the base station, and can be transmitted to the terminal through the macro cell or the cell link between the base station and the terminal, or the cell associated with the CC or the base station.

After transmitting the retransmission request status report, the base station receives the retransmission data unit through a cell link associated with the base station, the macro cell, or the wireless link between the terminal and the base station or the CC or the base station (S2040). The base station transmits and receives the retransmission request status report and the retransmission data unit through only the cell associated with the wireless link or the CC or the base station between the terminal and the base station, thereby solving the problem caused by the window stop and reducing the data delay.

A configuration of a base station and a terminal capable of performing all of the present invention described with reference to Figs. 7 to 20 will be described.

21 is a diagram illustrating a configuration of a UE in downlink and uplink situations according to another embodiment of the present invention.

21, a user terminal 2100 according to another embodiment of the present invention includes a receiving unit 2110, a control unit 2120, and a transmitting unit 2130.

In detail, a terminal 2100 constituting a dual connection with a first base station and a second base station according to the present invention in a downlink situation includes a receiving unit 2110 for receiving upper layer signaling including retransmission request path information from a first base station And generates a retransmission request status report for requesting retransmission of data units not received from the first base station and the second base station in the PDCP entity of the terminal, and generates a retransmission request status report for the RLC (Radio Link Control) And a control unit 2120 for transmitting a retransmission request status report to the RLC entity of the UE peered to the entity. The receiving unit 2110 receives the retransmission data unit requested by the PDCP entity of the UE through the retransmission request status report 1 through the RLC entity of the UE peered to the RLC entity of the first base station.

Meanwhile, the terminal 2100 forming a dual connection with the first base station and the second base station according to the present invention in the uplink state includes a receiving unit 2110 receiving the upper layer signaling including the retransmission path information from the first base station, And a control unit 2120 for transmitting a retransmission data unit from the PDCP entity of the UE to the RLC entity of the UE peered to the RLC entity of the first base station. The receiving unit 2110 receives the PDCP entity from the PDCP entity of the UE, 2 receives a retransmission request status report for requesting retransmission of a data unit that has not been received from the base station.

The control unit 2120 of the UE 2100 can control the data included in the retransmission buffer of the PDCP entity of the UE to be transmitted only to the RLC entity of the UE peered to the RLC entity of the first BS. The overall operation of the terminal according to the present invention can be controlled.

The receiving unit 2110 receives downlink control information, data, and messages from the base station through the corresponding channel.

The transmitting unit 2130 transmits downlink control information, data, and a message to the base station through the corresponding channel.

22 is a diagram illustrating a configuration of a base station in downlink and uplink situations according to another embodiment of the present invention.

22, a base station 2200 according to another embodiment of the present invention includes a control unit 2210, a transmission unit 2220, and a reception unit 2230.

A base station 2200 that forms a dual connection with a second base station according to the present invention in a downlink situation includes a transmitter 2220 that transmits upper layer signaling including retransmission request path information to a mobile station, An entity may receive a retransmission request status report 2230 for receiving a retransmission request of a data unit not received from the terminal and may transmit a control unit 2210 for transmitting a retransmission data unit from the PDCP entity of the base station to the RLC entity of the base station .

The controller 2210 of the base station 2200 may control the data included in the retransmission buffer of the base station PDCP entity to be transmitted only to the RLC entity of the base station and may control the overall operation of the base station according to the present invention .

Meanwhile, the base station 2200 that forms a dual connection with the second base station according to the present invention in the uplink situation includes a transmitter 2220 that transmits upper layer signaling including retransmission path information to the terminal, A control unit 2210 for generating a retransmission request status report for requesting retransmission of a data unit not received from the terminal in the PDCP entity and delivering a retransmission request status report to the RLC entity of the base station and a retransmission request status report And a receiver 2230 for receiving the requested retransmission data unit through the RLC entity of the base station.

The transmitting unit 2220 and the receiving unit 2230 are used to transmit and receive signals, messages, and data necessary for carrying out the present invention to and from the terminal.

According to the present invention as described above, there is an effect of reducing a window suspension problem in the process of reordering lost data by a terminal and a base station transmitting and receiving data by configuring a dual connection with a plurality of base stations.

In addition, there is an effect that the delay is reduced and the data is transmitted in order by constructing the double connection.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

Claims (27)

A method for processing data not received by a terminal constituting a dual connection with a first base station and a second base station,
Receiving an upper layer signaling including retransmission request path information from the first base station;
Generating a retransmission request status report for requesting retransmission of a data unit not received from the first base station and the second base station in a PDCP (Packet Data Convergence Protocol) entity of the UE; And
And forwarding the retransmission request status report from the PDCP entity of the UE to an RLC entity of the UE peered to an RLC entity of the first base station. The method according to claim 1,
Further comprising receiving a retransmission data unit requested by the PDCP entity of the UE through the retransmission request status report through the RLC entity of the UE peered to the RLC entity of the first base station. The method according to claim 1,
The retransmission request path information may include:
Information for setting up the PDCP entity of the UE to transmit the retransmission request status report to the RLC entity of the UE peered to the RLC entity of the first base station and information for setting the retransmission request status report to a cell associated with the first base station Or information to be set to be transmitted through a component carrier (CC). The method according to claim 1,
Wherein the retransmission request status report comprises:
PDCP status report. A method for transmitting data between base stations constituting a dual connection to a terminal together with a second base station,
Transmitting an upper layer signaling including retransmission request path information to the terminal;
Receiving a retransmission request status report for requesting retransmission of a data unit not received from the terminal in a Packet Data Convergence Protocol (PDCP) entity of the base station; And
And forwarding a retransmission data unit from a PDCP entity of the base station to a Radio Link Control (RLC) entity of the base station. 6. The method of claim 5,
The retransmission request path information may include:
Information for setting the retransmission request status report to be delivered to the RLC entity of the UE peered to the RLC entity of the base station in the PDCP entity of the UE and information for setting the retransmission request status report to a cell or a component carrier And information to be set up to be transmitted through a Component Carrier (CC). 6. The method of claim 5,
The retransmission request report includes:
PDCP status report. A method for transmitting data between a first base station and a second base station, the method comprising:
Receiving an upper layer signaling including retransmission path information from the first base station;
Receiving a retransmission request status report for requesting retransmission of a data unit not received from the first base station and the second base station in a Packet Data Convergence Protocol (PDCP) entity of the terminal; And
And forwarding a retransmission data unit to a RLC entity of the UE peered to a Radio Link Control (RLC) entity of the first base station in a PDCP entity of the UE. 9. The method of claim 8,
The retransmission path information includes:
Information for setting the retransmission data unit requested by the PDCP entity of the UE through the retransmission request status report of the first BS to be delivered to the RLC entity of the UE peered to the RLC entity of the first BS, And information for setting the retransmission data unit requested to be transmitted through the retransmission request status report of the first base station to be transmitted through a cell or a component carrier (CC) associated with the first base station Lt; / RTI > 9. The method of claim 8,
Wherein the retransmission request status report comprises:
PDCP status report. 9. The method of claim 8,
In the step of transmitting the retransmission data unit,
The data included in the retransmission buffer of the PDCP entity of the UE may be,
Wherein the RLC entity is only delivered to the RLC entity of the UE peered to the RLC entity of the first base station. A method for processing data not received by a base station having a dual connection with a second base station,
Transmitting an upper layer signaling including retransmission path information to the terminal;
Generating a retransmission request status report for requesting retransmission of a data unit not received from the terminal in a PDCP (Packet Data Convergence Protocol) entity of the base station;
Transferring the retransmission request status report from a PDCP entity of the base station to a Radio Link Control (RLC) entity of the base station; And
And receiving a retransmission data unit requested by the PDCP entity of the base station through the retransmission request status report through an RLC entity of the base station. 13. The method of claim 12,
The retransmission path information includes:
Information for setting up the retransmission data unit requested by the PDCP entity of the UE through the retransmission request status report of the BS to be delivered to the RLC entity of the UE peered to the RLC entity of the BS, And information for setting the retransmission data unit requested through the status report to be transmitted through a cell or a component carrier (CC) associated with the base station. 13. The method of claim 12,
Wherein the retransmission request status report comprises:
PDCP status report. A terminal in a dual connection with a first base station and a second base station,
A receiving unit for receiving upper layer signaling including retransmission request path information from the first base station; And
Generates a retransmission request status report for requesting retransmission of a data unit not received from the first base station and the second base station in a PDCP (Packet Data Convergence Protocol) entity of the UE,
And a controller for transmitting the retransmission request status report from the PDCP entity of the UE to an RLC entity of the UE peered to an RLC entity of the first BS,
Wherein the receiving unit receives the retransmission data unit requested through the retransmission request status report from the PDCP entity of the UE through the RLC entity of the UE peered to the RLC entity of the first BS. 16. The method of claim 15,
The retransmission request path information may include:
Information for setting up the PDCP entity of the UE to transmit the retransmission request status report to the RLC entity of the UE peered to the RLC entity of the first base station and information for setting the retransmission request status report to a cell associated with the first base station Or information to be set to be transmitted through a component carrier (CC). 16. The method of claim 15,
Wherein the retransmission request status report comprises:
PDCP status report. A base station that forms a dual connection to a terminal together with a second base station,
A transmitter for transmitting upper layer signaling including retransmission request path information to the terminal;
A receiving unit for receiving a retransmission request status report for requesting retransmission of a data unit not received from the terminal in a PDCP (Packet Data Convergence Protocol) entity of the base station; And
And a controller for transmitting a retransmission data unit from a PDCP entity of the base station to a Radio Link Control (RLC) entity of the base station. 19. The method of claim 18,
The retransmission request path information may include:
Information for setting the retransmission request status report to be delivered to the RLC entity of the UE peered to the RLC entity of the base station in the PDCP entity of the UE and information for setting the retransmission request status report to a cell or a component carrier And information to be set up to be transmitted through a Component Carrier (CC). 19. The method of claim 18,
Wherein the retransmission request status report comprises:
PDCP status report. A terminal in a dual connection with a first base station and a second base station,
A receiving unit for receiving upper layer signaling including retransmission path information from the first base station; And
And a controller for transmitting a retransmission data unit to a Radio Link Control (RLC) entity of the terminal peered to the RLC entity of the first base station in a PDCP (Packet Data Convergence Protocol) entity of the UE,
Wherein the receiver receives a retransmission request status report for requesting retransmission of a data unit not received from the first base station and the second base station in a PDCP entity of the terminal. 22. The method of claim 21,
The retransmission path information includes:
Information for setting the retransmission data unit requested by the PDCP entity of the UE through the retransmission request status report of the first BS to be delivered to the RLC entity of the UE peered to the RLC entity of the first BS, And information for setting the requested retransmission data unit to be transmitted through a cell or a component carrier (CC) associated with the first base station through a retransmission request status report of the first base station. . 22. The method of claim 21,
Wherein the retransmission request status report comprises:
PDCP status report. 22. The method of claim 21,
In delivering the retransmission data unit,
Wherein the data included in the retransmission buffer of the PDCP entity of the UE is only delivered to the RLC entity of the UE peered to the RLC entity of the first base station. A base station that forms a dual connection to a terminal together with a second base station,
A transmitter for transmitting upper layer signaling including retransmission path information to the terminal;
A Packet Data Convergence Protocol (PDCP) entity of the base station generates a retransmission request status report for retransmission of a data unit not received from the terminal and transmits the retransmission request status report to the RLC entity of the base station A control unit; And
And a receiver for receiving a retransmission data unit requested by the PDCP entity of the base station through the retransmission request status report through an RLC entity of the base station. 26. The method of claim 25,
The retransmission path information includes:
Information for setting up the retransmission data unit requested by the PDCP entity of the UE through the retransmission request status report of the BS to be delivered to the RLC entity of the UE peered to the RLC entity of the BS, And information for setting the retransmission data unit requested through the status report to be transmitted through a cell or a component carrier (CC) associated with the base station. 26. The method of claim 25,
Wherein the retransmission request status report comprises:
PDCP status report.

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